org.abora.white.collection.tables
Class ActualHashTable

java.lang.Object
  |
  +--org.abora.white.xpp.basic.Heaper
        |
        +--org.abora.white.collection.tables.ScruTable
              |
              +--org.abora.white.collection.tables.MuTable
                    |
                    +--org.abora.white.collection.tables.HashTable
                          |
                          +--org.abora.white.collection.tables.ActualHashTable

public class ActualHashTable

extends HashTable

The HashTable is an implementation class that is intended to provide the weakest Position->Object mapping. It can map from arbitrary Position classes (such as HeaperAsPosition or TreePosition). HashTable can also be used for very sparse integer domains. HashTable, and the entire hashtab module, is private implementation. Not to be included by clients.

Field Summary

protected CoordinateSpace	myCoordinateSpace
protected SharedPtrArray	myHashEntries
protected int	myTally

Constructor Summary

ActualHashTable(Rcvr receiver)

ActualHashTable(SharedPtrArray entries, int tally, CoordinateSpace cs)

Method Summary

void	aboutToWrite() If my contents are shared, and I'm about to change them, make a copy of them.
Heaper	atIntStore(IntegerValue key, Heaper aHeaper) Unboxed version.
Heaper	atStore(Position key, Heaper aHeaper) Associate value with key, whether or not there is a previous association.
void	checkSize()
CoordinateSpace	coordinateSpace() The kind of elements used to index into the table are Positions of this coordinate space.
ScruTable	copy() A new one whose initial state is my current state, but that doesn't track changes.
IntegerValue	count() Return the number of domain elements, which is to say, the number of associations.
void	destruct()
XnRegion	domain() Return an XuRegion representing a snapshot of the current domain.
ScruTable	emptySize(IntegerValue size) Return an empty table just like the current one.
int	fastHash()
Heaper	fetch(Position key) Return the range element at the domain position key.
boolean	includesKey(Position aKey) includesKey is used to test for the presence of a key->value pair in the table.
Heaper	intFetch(IntegerValue key) Unboxed version.
boolean	isEmpty() Is there anything in the table? 'table->isEmpty()' iff 'table->domain()->isEmpty()'.
static MuTable	make(CoordinateSpace cs) A new empty MuTable whose domain space is 'cs'.
static HashTable	make(CoordinateSpace cs, IntegerValue size)
void	printOn(java.io.PrintWriter oo) This should rarely be overridden.
void	receiveHashTable(Rcvr rcvr) This currently doesn't take advantage of the optimizations in TableEntries.
XnRegion	runAt(Position index) Return the length of the run starting at position key.
void	sendHashTable(Xmtr xmtr) This currently doesn't take advantage of the optimizations in TableEntries.
void	sendSelfTo(Xmtr xmtr)
TableStepper	stepper(OrderSpec order) ignore order spec for now
void	storeEntry(TableEntry anEntry) Store the tableentry into the entry table
ScruTable	subTable(XnRegion region) Return a table which contains only the intersection of this table's domain and the domain specified by 'region'.
Heaper	theOne() Iff I contain exactly one range element, return it.
boolean	wipe(Position aKey) Remove a key->value association from the table.

Methods inherited from class org.abora.white.collection.tables.MuTable

actualHashForEqual, asImmuTable, asMuTable, atIntIntroduce, atIntReplace, atIntroduce, atReplace, includesIntKey, intRemove, introduceAll, introduceAll, introduceAll, intWipe, isEqual, make, problems, remove, removeAll, replaceAll, replaceAll, replaceAll, runAtInt, storeAll, storeAll, storeAll, wipeAll

Methods inherited from class org.abora.white.collection.tables.ScruTable

backfollowFrom, contentsEqual, contentsHash, get, intGet, printOnWithSimpleSyntax, printOnWithSyntax, range, stepper, transformedBy

Methods inherited from class org.abora.white.xpp.basic.Heaper

destroy, equals, hashForEqual, printContentsOn, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

myHashEntries

protected SharedPtrArray myHashEntries

myTally

protected int myTally

myCoordinateSpace

protected CoordinateSpace myCoordinateSpace

Constructor Detail

ActualHashTable

public ActualHashTable(SharedPtrArray entries,
                       int tally,
                       CoordinateSpace cs)

ActualHashTable

public ActualHashTable(Rcvr receiver)

Method Detail

atStore

public Heaper atStore(Position key,
                      Heaper aHeaper)

Description copied from class: HashTable

Associate value with key, whether or not there is a previous association.

Specified by:

atStore in class HashTable

atIntStore

public Heaper atIntStore(IntegerValue key,
                         Heaper aHeaper)

Description copied from class: MuTable

Unboxed version. See class comment for XuInteger

Overrides:

atIntStore in class MuTable

coordinateSpace

public CoordinateSpace coordinateSpace()

Description copied from class: ScruTable

The kind of elements used to index into the table are Positions of this coordinate space. Therefore, the domain of this table is an XuRegion in this coordinate space.

Specified by:

coordinateSpace in class HashTable

count

public IntegerValue count()

Description copied from class: ScruTable

Return the number of domain elements, which is to say, the number of associations. 'table->count()' should be equivalent to 'table->domain()->count()'. Used to say: 'Return the number of range elements'. This seems clearly wrong.

Specified by:

count in class HashTable

domain

public XnRegion domain()

Description copied from class: ScruTable

Return an XuRegion representing a snapshot of the current domain. 'table->domain()->hasMember(p)' iff 'table->fetch(p) !!= NULL'.

Specified by:

domain in class HashTable

fetch

public Heaper fetch(Position key)

Description copied from class: ScruTable

Return the range element at the domain position key. The routine will return NULL if the position is not in the table.

Specified by:

fetch in class HashTable

intFetch

public Heaper intFetch(IntegerValue key)

Description copied from class: ScruTable

Unboxed version. See class comment for XuInteger

Overrides:

intFetch in class MuTable

subTable

public ScruTable subTable(XnRegion region)

Description copied from class: ScruTable

Return a table which contains only the intersection of this table's domain and the domain specified by 'region'. table->subTable(r)->domain()->isEqual( table->domain()->intersect(r) ). It is unspecified whether the resulting table starts as a snapshot of a subset of me, after which we go our own ways; or whether the resulting table is a view onto a subset of me, such that changes to me are also visible to him. Of course, subclasses may specify more. If you want to ensure snapshot behavior, do 'table->subTable(r)->asImmuTable()'. NOTE: In the future we may specify snapshot behavior or we may specify view behavior. As a client this shouldn't effect you. However, if you implement a new kind of ScruTable, please let us know. Also, if you have an opinion as to which way you'd like the specification tightened up, please tell us.

Specified by:

subTable in class HashTable

wipe

public boolean wipe(Position aKey)

Description copied from class: HashTable

Remove a key->value association from the table. Do not blast (or do anything else) if the key is not in my current domain.

Specified by:

wipe in class HashTable

fastHash

public int fastHash()

includesKey

public boolean includesKey(Position aKey)

Description copied from class: ScruTable

includesKey is used to test for the presence of a key->value pair in the table. This routine returns true if there is a value present at the specified key, and false otherwise. 'table->includesKey(p)' iff 'table->domain()->hasMember(p)'.

Specified by:

includesKey in class HashTable

isEmpty

public boolean isEmpty()

Description copied from class: ScruTable

Is there anything in the table? 'table->isEmpty()' iff 'table->domain()->isEmpty()'.

Specified by:

isEmpty in class HashTable

copy

public ScruTable copy()

Description copied from class: ScruTable

A new one whose initial state is my current state, but that doesn't track changes. Note that there is no implication that these can be 'destroy'ed separately, because (for example) an ImmuTable just returns itself

Specified by:

copy in class HashTable

emptySize

public ScruTable emptySize(IntegerValue size)

Description copied from class: ScruTable

Return an empty table just like the current one. The 'size' argument is a hint about how big the count of the table will probably become (so that the new table can be prepared to grow to that size efficiently).

Specified by:

emptySize in class HashTable

printOn

public void printOn(java.io.PrintWriter oo)

Description copied from class: Heaper

This should rarely be overridden. In Tofu, it prints ClassName(...), where ... is either produced by printInsideOn or is ??? if printInsideOn it not overridden.

Overrides:

printOn in class ScruTable

runAt

public XnRegion runAt(Position index)

Description copied from class: ScruTable

Return the length of the run starting at position key. A run is defined as a contiguous (charming) sequence of domain positions mapping to equal (isEqual) objects. Charming is defined as: Given a charming region R, for all a,c which are elements of R and a >= b >= c, b is an element of R. Where '>=' is according to the 'isGE' message. NOTE: We may retire the above definition of charming. The possible changes will only effect spaces which aren't fully ordered. OrderedRegions, TreeRegions, and IntegerRegions will be unaffected, as any future definition of 'runAt' will be equivalent for them.

Specified by:

runAt in class HashTable

stepper

public TableStepper stepper(OrderSpec order)

ignore order spec for now

Specified by:

stepper in class HashTable

theOne

public Heaper theOne()

Description copied from class: ScruTable

Iff I contain exactly one range element, return it. Otherwise BLAST. The idea for this message is taken from the THE function of ONTIC (reference McAllester)

Specified by:

theOne in class HashTable

receiveHashTable

public void receiveHashTable(Rcvr rcvr)

This currently doesn't take advantage of the optimizations in TableEntries. It should.

sendHashTable

public void sendHashTable(Xmtr xmtr)

This currently doesn't take advantage of the optimizations in TableEntries. It should.

destruct

public void destruct()

Overrides:

destruct in class Heaper

aboutToWrite

public void aboutToWrite()

If my contents are shared, and I'm about to change them, make a copy of them.

checkSize

public void checkSize()

storeEntry

public void storeEntry(TableEntry anEntry)

Store the tableentry into the entry table

sendSelfTo

public void sendSelfTo(Xmtr xmtr)

Overrides:

sendSelfTo in class MuTable

make

public static MuTable make(CoordinateSpace cs)

Description copied from class: MuTable

A new empty MuTable whose domain space is 'cs'.

make

public static HashTable make(CoordinateSpace cs,
                             IntegerValue size)